Many documents are protected for various different reasons using various different methods. For example, documents can be protected from copying, forging and counterfeiting using different methods including security printing.
Some security printing requires specialty hardware and/or materials. For example, a specialty document can be used for prescriptions where a pharmacist would like to be able to have a good level of confidence that the document is genuine.
Security printing may require a key to decipher the security image that is printed. Some security printing requires multiple different keys to be placed on top of the image and rotated until the image is deciphered. This can be inefficient and time consuming.